On May 2, a crowd of about 800 assembled on campus, disrupted a dance in a university hall, smashed the windows of the ROTC building, and threw lighted railroad flares inside.

The building burned to the ground.

A professor who watched the arson later told the Scranton commission, which investigated the shooting and the events leading up to it, "I have never in my 17 years of teaching seen a group of students as threatening, or as arrogant, or a bent on destruction."

The Guard, consisting of a hundred men surrounded by rioters shouting obscenities and chanting "Kill, kill, kill," were under a constant barrage of rocks, chunks of concrete and cinderblock, and canisters. Fifty-eight Guardsmen were injured by thrown objects. Several of them were knocked to the ground.

The Guardsmen retreated up the hill, appearing frightened, and then some of them suddenly turned and fired for thirteen seconds.